A common defence for storing data as flat tables is:
Joins are expensive
But is that really true?
Thomas Kejser ran performance tests and found
Joins are CHEAP when compared with the alternatives
This can be true even if you read the whole table
buff.ly/AFykOZF
Joins are NOT Expensive! - Raw ReadingWhen talking about Data Lakes and how people access them - we must address some of the misconceptions that made them popular in the first place.
